JP2002265511A - Method of producing partial neutralization product of polyacrylic acid and sticking agent using the product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a method of producing a partial neutralization product of polyacrylic acid satisfactory in release from a production apparatus such as a production vessel and satisfactory in uniformity and solubility in a process of milling with water, a solvent, or the like. SOLUTION: This method is characterized adding 0.01-4 wt.%, based on the weight of the monomers, polyethylene glycol of an average molecular weight of 3,000-50,000 to an aqueous monomer solution containing acrylic acid and an alkali metal salt thereof as the monomers and polymerizing the monomers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a partially neutralized product of polyacrylic acid, especially a partially neutralized product of non-crosslinked polyacrylic acid, and a patch using the neutralized product.

[0002]

2. Description of the Prior Art Uncrosslinked polyacrylic acid partially neutralized products are used, for example, as thickeners for Tomoe. For example, JP-A-10-237110 describes a method for producing an aqueous solution in which acrylic acid is partially neutralized with sodium hydroxide or a mixed aqueous solution of acrylic acid and sodium acrylate is subjected to static polymerization. . A method is also known in which a partially neutralized acrylic acid is polymerized in the presence of a low-molecular-weight polyethylene glycol (Japanese Patent Application Laid-Open No. 55-55).
84304). In other words, Japanese Patent Application Laid-Open No. 55-84304 discloses that a water-absorbent resin used in a disposable disposable diaper or the like is made of acrylic acid in the presence of low-molecular-weight (molecular weight 400) polyethylene glycol or glycerin in order to improve the water-absorbing ability and tackiness. The partially neutralized product is subjected to water-soluble polymerization to obtain a gel-like hydrated polymer, which is then dried by heating at 180 to 200 ° C., whereby the carboxylic acid of the polymer and the hydroxyl group of low-molecular-weight polyethylene glycol or glycerin are converted. A method for producing a crosslinked product of an alkali metal polyacrylate by a crosslinking reaction based on esterification has been obtained. A method of polymerizing acrylic acid or a salt thereof in the presence of a high molecular weight polyethylene glycol is also known (Japanese Patent Laid-Open No. 3-24 / 1991).
3680, JP-A-55-722). That is, JP-A-3-243680 discloses that an ethylenically unsaturated monomer is added in the presence of water in the presence of a polyol such as polyethylene glycol to a weight ratio of 5:95 to improve adhesion and adhesion. 95: 5, that is, 5 to 5, based on the weight of the ethylenically unsaturated monomer.
95% by weight was added and polymerized to obtain a tacky / adhesive solution, which was dried, and then poured again with water to obtain a hydrophilic pressure-sensitive adhesive composition as a hydrogel. JP-A-55-722 discloses that an aqueous solution of (A) water and (B) a water-soluble polymer such as polyethylene glycol is added to (C) a water-soluble ethylenically unsaturated monomer such as sodium acrylate. Is polymerized in a weight ratio of (B) to (C) of 10: 1 to 1:10 to obtain an aqueous dispersion of a water-soluble polymer composite.

[0003]

However, when the partially neutralized polyacrylic acid obtained by the above-mentioned conventional production method (JP-A-10-237110) is kneaded using water and / or a solvent, the solubility and Difficulty in uniformity. Furthermore, in this method, what is obtained by polymerization is a hydrogel, and its releasability from a manufacturing apparatus such as a polymerization vessel is poor due to its high adhesiveness.
Had working disadvantages. Also, Japanese Patent Application Laid-Open No. 55-843, which is polymerized in the presence of low molecular weight polyethylene glycol.
In the method described in No. 04, the obtained hydrogel is not cross-linked, but cross-linked when dried, and a partially cross-linked polyacrylic acid neutralized product cannot be obtained. Further, Japanese Patent Application Laid-Open No.
According to the methods described in JP-A-243680 and JP-A-55-722, what is obtained by polymerization is in the form of a solution, and cannot be obtained in the form of a hydrogel that is easily dried, and it takes a long time to dry.

[0004]

Means for Solving the Problems The present inventors have conducted various studies in order to solve the above-mentioned problems, and as a result, have found that polyethylene glycol having a specific average molecular weight is added to an aqueous monomer solution containing partially neutralized acrylic acid. When a specific amount is added to the weight of the monomer and polymerized, an uncrosslinked hydrogel polyacrylic acid partially neutralized product having good releasability from a manufacturing device such as a container is obtained, and dried. It has been found that the obtained partially neutralized polyacrylic acid has properties of good uniformity and solubility in solvents.

That is, the present invention relates to the following items (1) to (8). (1) An aqueous monomer solution containing acrylic acid and an alkali metal salt of acrylic acid as a monomer has an average molecular weight of 3,000 to 3,000.
A method for producing a gel-like partially neutralized polyacrylic acid, wherein 50,000 polyethylene glycol is added in an amount of 0.01 to 4% by weight based on the total weight of the monomer, followed by polymerization. (2) An aqueous monomer solution containing acrylic acid and an alkali metal salt of acrylic acid as a monomer has an average molecular weight of 3,000 to 3,000.
50,000 polyethylene glycol is added in an amount of 0.01 to 4% by weight based on the total weight of the monomer, and the mixture is polymerized to obtain a gel polymer, which is then dried. Manufacturing method of goods. (3) The production method according to (1) or (2), wherein the alkali metal salt of acrylic acid is sodium acrylate. (4) The method according to any one of (1) to (3), wherein the polymerization is static polymerization. (5) 40 to 60% of the carboxyl groups present in the partially neutralized polyacrylic acid are alkali metal salts (1) to
The production method according to any one of (4). (6) The production method according to (2), wherein the drying temperature is 110 to 150 ° C. (7) The method according to any one of (1) to (6), wherein the partially neutralized polyacrylic acid is not substantially crosslinked. (8) A patch using the partially neutralized polyacrylic acid obtained by the production method according to any one of (1) to (7).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The production method of the present invention comprises the steps of: adding a polyethylene glycol having an average molecular weight of 3,000 to 50,000 to an aqueous monomer solution containing acrylic acid and an alkali metal salt of acrylic acid as a monomer; 0.0 to weight
It is characterized by adding 1 to 4% by weight and polymerizing. The partially neutralized polyacrylic acid obtained by this method is an uncrosslinked gel containing water. Further, by drying this, an uncrosslinked, partially neutralized polyacrylic acid in a dry state is obtained.

The alkali metal salt of acrylic acid used in the present invention includes, for example, sodium acrylate and potassium acrylate, but sodium acrylate is preferred.

The aqueous monomer solution is usually prepared by adding an alkali such as sodium hydroxide or potassium hydroxide (preferably an alkali solution) to an aqueous solution of acrylic acid, or by adding an alkali metal salt of acrylic acid. It can be obtained by mixing an aqueous solution and an aqueous solution of acrylic acid.

The total concentration of the monomers in the aqueous monomer solution is not particularly limited as long as it is a uniform solution, but is usually 50% or less, preferably 10 to 50%. Further, from the viewpoint of heat of polymerization and production efficiency, 20 to 40% is more preferable.

The polyethylene glycol used in the present invention generally has an average molecular weight in the range of 3,000 to 50,000, preferably in the range of 10,000 to 30,000. As this polyethylene glycol, a commercially available polyethylene glycol can be used. The amount used is in the range of 0.01% to 4% by weight, preferably 0.1% to 2% by weight, based on the total weight of the monomers.

In order to carry out the production method of the present invention, for example, polyethylene glycol having an average molecular weight of 3,000 to 50,000 is added to an aqueous monomer solution containing acrylic acid and an alkali metal salt of acrylic acid, based on the total weight of the monomer. 0.01 ~
A polymerization stock solution is prepared by adding 4% by weight, preferably after degassing (deoxygenation), and after adding additives such as a polymerization catalyst, the polymerization is carried out preferably in a polymerization vessel, preferably by static polymerization. May be taken out of the polymerization vessel and dried if desired.

The aqueous monomer solution can be prepared by various methods. That is, the carboxyl group in the monomer is 40 to
An alkali such as sodium hydroxide or potassium hydroxide is added to the aqueous solution of acrylic acid so that the alkali metal salt becomes 60%, preferably 45 to 55%, or the carboxyl group in the monomer is 40 to 60%, preferably 45-55%
It can be prepared by adding an aqueous solution of acrylic acid to an aqueous solution of an alkali metal acrylate so as to become an alkali metal salt. An aqueous solution of an alkali metal acrylate is prepared by adding an alkali such as sodium hydroxide or potassium hydroxide to an aqueous solution of acrylic acid so that all the carboxyl groups in the acrylic acid become alkali metal salts. When present, it can be obtained by removing the polymerization inhibitor with activated carbon or the like as necessary.

The polymerization stock solution can be obtained by adding polyethylene glycol directly or as a solution in a solvent such as water to the aqueous solution of the partially neutralized acrylic acid monomer obtained by the above method. When polyethylene glycol is dissolved in a solvent, the amount of the solvent may be any amount as long as the polyethylene glycol can be dissolved. The solvent is preferably water.

The deaeration of the polymerization stock solution may be carried out, for example, by introducing nitrogen gas into the stock solution and treating for 0.5 to 2 hours.

The polymerization is preferably carried out by static polymerization, and is carried out by adding an additive such as a polymerization catalyst to the stock polymerization solution. The polymerization initiation temperature is generally in the range of 0 to 50 ° C, preferably 10 to 50 ° C.
-30 ° C. The temperature during the polymerization is usually in the range of 0 ° C to the boiling temperature, preferably 10 to 100 ° C. The polymerization time is usually 5 to 30 hours.

The polymerization initiator may be any water-soluble one. Specifically, sodium persulfate, potassium persulfate,
Persulfates such as ammonium persulfate; and azobis compounds such as 2,2-azobis (2-amidinopropane) hydrochloride. The polymerization initiator can be used usually in an amount of 10 to 100 ppm based on the weight of the polymerization stock solution.

In the present invention, for example, a polymerization accelerator or a polymerization degree regulator can be used as an additive. The polymerization accelerator has a function of activating a polymerization initiator such as persulfate, and examples thereof include bisulfite such as sodium bisulfite, L-ascorbic acid, and the like, and it is preferable to use both in combination. . The polymerization accelerator can be used usually at 1 to 10 ppm based on the weight of the polymerization stock solution.
Further, the polymerization degree regulator has a function of adjusting the degree of polymerization, and for example, it is preferable to use a chain transfer agent such as sodium hypophosphite. Polymerization degree regulator,
Usually, 30 to 150 ppm can be used based on the weight of the polymerization stock solution.

The polymerization initiator, polymerization accelerator or chain transfer agent may be used as it is, or may be used after being dissolved in a solvent such as water. The amount of the solvent may be in any range as long as it can dissolve the polymerization initiator, the polymerization accelerator or the chain transfer agent.

The polymer obtained by the above method is a gel-like partially neutralized water-containing polyacrylic acid. The partially neutralized water-containing polyacrylic acid usually contains 50% or more of water, preferably 50 to 90%, more preferably 60 to 8%.
Contains 0%. Since the partially neutralized product of polyacrylic acid obtained by polymerization is in a gel state, it has a higher concentration than that obtained by an aqueous solution. Therefore, the labor (time and energy for heating) required for the subsequent drying can be reduced, so that the partially neutralized polyacrylic acid can be efficiently produced.

By drying the gel-like partially neutralized water-containing polyacrylic acid, a partially neutralized polyacrylic acid in a dry state is obtained. This drying is performed, for example, at 110 to
A method of drying by heating at 150 ° C. using a hot air dryer for 1 to 6 hours or a method of vacuum drying at a temperature of 20 to 80 ° C. using a vacuum dryer for 5 to 48 hours is adopted. A polymer (partially neutralized polyacrylic acid) can be obtained by drying the gel-like water-containing partially neutralized polyacrylic acid.

The partially neutralized polyacrylic acid product obtained in the present invention is one in which neither the hydrogel product nor the dried product is substantially crosslinked. Here, the term "substantially not crosslinked" means that, as shown in Test Example 3, a partially neutralized polyacrylic acid is added to a saline solution, stirred, and allowed to stand. 0.074 mm), which means that there is substantially no difference between the dry weight of the sieve before filtration and the dry weight of the sieve after filtration. That is, it indicates that there is no partially neutralized polyacrylic acid dissolved in the saline solution and filtered out of the system.

The partially neutralized polyacrylic acid is preferably one in which 40 to 60% of the carboxyl groups present are partially neutralized with an alkali metal salt such as sodium or potassium, preferably 45 to 55%. Are more preferred. The partial neutralization amount is measured by a method such as acid-alkali titration. Its viscosity is 0.2% of the partially neutralized polyacrylic acid.
% Aqueous solution with a B-type viscometer (rotor No. 2).
Measured at 0 ° C. and 30 rpm, usually 400 to 700 m
Pa · s, preferably 500 to 600 mP
and the pH is usually in the range of 5.5 to 7.5 in the 0.2% concentration aqueous solution.

The average molecular weight is not particularly limited, but is usually in the range of 1,000,000 to 100,000,000, preferably 20,000 to 50,000.
00 range. This average molecular weight is determined by GPC
(Gel permeation chromatography) -measured under the following measurement conditions by HPLC analysis. Column; T
SKgel GMPWxLx2, flow rate: 1.0 ml / mi
n, detector: RI (differential refractometer), concentration: 0.2 mg /
ml, injection volume; 100 μl, pressure; 10 kgf / c
m ² , column temperature; 40 ° C., system temperature; 40 ° C., eluent: 0.2 M NaNO ₃ .

In the present invention, since the polyethylene glycol having the above-mentioned molecular weight is used, the crosslinked polyacrylic acid partially neutralized product is hardly produced in both the gel and the dried product. Further, as a result of adding polyethylene glycol before polymerization, the partially neutralized acrylic acid and polyethylene glycol are uniformly mixed and polymerized, so that the partially neutralized polyacrylic acid obtained is also homogeneous. .

The patch of the present invention uses the partially neutralized polyacrylic acid obtained by the above-mentioned production method. Examples of the patch include preparations for transdermal absorption, preparations for transmucosal absorption, and the like. The patch is usually composed of a support such as a plaster or a nonwoven fabric in which each component is mixed. For the plaster, for example, in addition to partially neutralized polyacrylic acid (the blending amount is usually 5.0 to 10% by weight of the whole plaster), appropriate components that are usually used are used. For example, humectants {polyhydric alcohol (the amount is usually about 5.0 to 60% by weight of the whole plaster)}, inorganic powder (the compounding amount is usually 0.1% of the whole plaster)
To about 30% by weight), the active ingredient (the amount is usually about 0.1 to 20% by weight of the whole plaster), physical properties of the plaster (flexibility,
An adjuster (polymeric substance) for tackiness, shape retention, etc.) or a stable compounding agent for the active ingredient is used. Each of these components is 1
Species or two or more can be used. Further, the obtained plaster can be spread on a support (packing) such as paper, woven fabric, non-woven fabric, and plastic film, and can be subjected to a facing treatment using a polyethylene film or the like as necessary. .

Examples of the humectant (polyhydric alcohol) include propylene glycol, polyethylene glycol, glycerin and sorbitol, and examples of the inorganic powder include kaolin, bentonite, montmorillonite, zinc oxide, titanium oxide and anhydrous Silicic acid and the like can be mentioned, and examples of the modifier for the physical properties of the plaster (polymer substance) include guar gum, xanthan gum, gum arabic, starch derivatives, polybutene, latex, vinyl acetate emulsion and acrylic resin emulsion.

Examples of the active ingredient include methyl salicylate, glycol salicylate, indomethacin,
-Menthol, peppermint oil, eucalyptus oil, dl-camphor, pepper extract, vanillyl amide nonylate, vitamin E, diphenhydramine, chlorpheniramine maleate or thymol. Examples of the stable compounding agent of the active ingredient include lanolin, liquid paraffin, vegetable oil, lard, beef tallow, higher alcohol, higher fatty acid, nonionic, anionic, cationic or amphoteric activator.

As the patch, a polyvalent metal salt for crosslinking the partially neutralized polyacrylic acid is usually used. As the polyvalent metal salt, for example, a calcium salt, a magnesium salt, an aluminum salt, an iron salt or the like is used. Examples of the calcium salt include calcium chloride, calcium hydroxide, calcium carbonate and calcium phosphate. Examples of the magnesium salt include magnesium chloride, magnesium sulfate and magnesium carbonate. Examples of the aluminum salt include aluminum chloride, aluminum sulfate, and aluminum hydroxide. Examples of iron salts include ferric sulfate and ferric hydroxide.

For the patch, a crosslinking agent such as potassium alum, ammonium alum, iron alum or dihydroxyaluminum aminoacetate, a pH regulator such as tartaric acid, a binder such as gelatin, and water such as purified water are also used. . The amount of tartaric acid used is usually about 0.1 to 10% by weight of the whole plaster.

To produce the patch of the present invention, for example,
First, a pH adjuster, an active ingredient, an inorganic powder, a binder and water are mixed. Separately, the partially neutralized polyacrylic acid obtained in the present invention, a crosslinking agent and a humectant are mixed. Then, the two mixtures are mixed and uniformly kneaded to obtain a paste-like gel plaster for a patch,
This can be obtained by coating and spreading on a nonwoven fabric and protecting it with a polyethylene film. The temperature at which these mixings are performed is usually 0 to 40 ° C, preferably 10 to 35 ° C.

[0031]

Test Examples Hereinafter, the present invention will be described specifically with reference to test examples, but the present invention is not limited thereto.

Test Example 1 Measurement of Uniformity and Solubility by Torque Meter Test Method Sample in a 500 mL beaker (9.00 g of the partially neutralized polyacrylic acid (A) obtained in Example 2 and Comparative Example 1) The resulting partially neutralized polyacrylic acid (B) 9.0
Prepare 0 g and add 30.00 g of glycerin. Next, each of them was supplied with a torque meter device (Satake Chemical Machinery Co., Ltd.,
ORQUE METER ST-1000 type, 4 paddle blade stirring), stirring (150 rpm), dispersion, and then adding purified water (161.00 g) with stirring.
A torque measurement was performed. Table 1 shows the results.

Table 1 Uniformity / Solubility by Torque Meter Maximum Torque Maximum Amplitude Melting Time Uniformity / Solubility A 490 g · cm 60 g · cm 4.0 minutes ○ B 620 g · cm 180 g · cm 12.5 minutes ×

In Table 1, the partially neutralized polyacrylic acid obtained in Example 2 (A) had a smaller torque than the partially neutralized polyacrylic acid (B) obtained in Comparative Example 1. And dissolved. As a result, it was found that the polyacrylic acid partially neutralized product of the present invention obtained in Example 2 had improved uniformity and solubility.

Test Example 2 Measurement of Releasability by Rheometer Test Method Partially neutralized hydrous polyacrylic acid obtained in Example 1 (C) and partially neutralized hydrous polyacrylic acid obtained in Comparative Example 1 After cutting (D), the adhesiveness (release property) of the cut surface was measured using a rheometer (Reotech Co., Ltd., immovable RHEOMETER / load: 200 g / measuring adapter: stainless steel disk with a diameter of 10 mm). . Table 2 shows the results.

Table 2 Releasing property by rheometer Rheometer adhesiveness Releasability C 89 g ○ D 148 g ×

In Table 2, the partially hydrolyzed polyacrylic acid partially neutralized product (C) obtained in Example 1 is more excellent than the partially hydrolyzed polyacrylic acid partially neutralized product (D) obtained in Comparative Example 1. It turned out that it peeled off with a small force. As a result, it was found that the partially neutralized hydrated polyacrylic acid product of the present invention obtained in Example 1 had improved releasability.

Test Example 3 Confirmation of Non-Crosslinked Body Test Method A 500 mL sample was placed in a beaker. Each of 1.00 g of the partially neutralized polyacrylic acid (A) obtained in Example 2 and the poly obtained in Comparative Example 1 was used. Acrylic acid partially neutralized product (B) 1.0
Prepare 0g, add 300g of 0.9% saline solution to each, add｝, stir for 6 hours, and let stand still overnight, then add 200g
Measure the weight of the mesh before filtering with a mesh mesh (sieve),
Next, the mixture was filtered through a 200-mesh screen (sieve), washed with purified water (500 g), dried with hot air at 60 ° C. for 3 hours, weighed, and the weight of the screen (sieve) was measured. The measurement is carried out (this measurement method was carried out according to the measurement method described in Example 1 of JP-A-55-84304 concerning the analysis of crosslinked products). Table 3 shows the results.

Table 3 Confirmation of non-crosslinking property Weight of the network before filtration Weight of the network after filtration and drying Amount of crosslinked product Crosslinkable A 226.97 g 226.97 g 0.00 g No B 226.97 g 226.97 g 0.00 g Nothing

In Table 3, the partially neutralized polyacrylic acid (A) obtained in Example 2 and the partially neutralized polyacrylic acid (B) obtained in Comparative Example 1 were both dispersed in saline. No crosslinked gel was found on the network before filtration and on the network after filtration and drying. Further, from the result that the net after filtration and washing was dried and the weight was not measured even when the weight was measured, the partially neutralized polyacrylic acid (A) of the present invention obtained in Example 2 was crosslinked. It was confirmed that the body was substantially free.

[0041]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 (polyethylene glycol 0.5
% Product) Neutralization process Water (2615 L), 60% acrylic acid (2626 mL /
After charging 2557 g / 22.98 M) and 48% sodium hydroxide (1149 mL / 1735 g / 20.82 M), the pH is adjusted to 11 by adding 48% sodium hydroxide. Next, activated carbon (about 50 g) was added and stirred.
Five hours later, a 29% aqueous sodium acrylate solution was obtained by filtration and washing with water. Preparation Step of Polymerization Stock Solution (Monomer Aqueous Solution of Partially Neutralized Acrylic Acid) A 29% aqueous solution of sodium acrylate (2879 mL / 3282 g / 10.126 M) obtained by filtration and 60%
% Acrylic acid aqueous solution (1124 mL / 1180 g / 9.
835M) and a partially neutralized aqueous solution of acrylic acid (40
03 mL / 4491 g / 19.961 M), to which polyethylene glycol (equivalent to 8.3 g / 0.5%)
By adding and dissolving the polymer (molecular weight: 20,000), an about 35% polymerization stock solution (polymer equivalent: 1668 g) was obtained. Polymerization Step The polymerization stock solution (dissolved oxygen 1 ppm or less / 700 mL / 3.49 mol) degassed using nitrogen was added as a catalyst to 22.
5% sodium hypophosphite monohydrate aqueous solution (0.20 g
/0.42 mM), 7.5% aqueous solution of ammonium persulfate (0.20 g / 0.066 mM) and 0.75% aqueous solution of L-ascorbic acid (0.20 g / 0.0085 mM)
Was added at an internal temperature of about 20 to 25 ° C., and then subjected to static polymerization for about 8 hours while cooling at a water temperature of 20 ± 5 ° C., and further for about 8 hours at a water temperature of 75 ± 5 ° C. Drying / Pulverization Step The obtained water-containing polymer is granulated, and after about 1 hour at 140 ± 5 ° C., is further pulverized and dried at 110 to 120 ° C. for 1 to 3 hours to obtain polyethylene glycol 0 as an objective substance. A partially neutralized polyacrylic acid containing 0.5% was quantitatively obtained. The pH of the resulting partially neutralized polyacrylic acid containing 0.5% of polyethylene glycol was 6.5 in a 0.2% concentration aqueous solution, and the monomer content in the partially neutralized polyacrylic acid was 0.5. The rotational viscosity of a 2% polyacrylic acid partially neutralized product was determined by measuring a 0.2% aqueous solution thereof under a B-type viscometer (rotor No. 2, 20 ° C., 30 rpm).
43 mPa · s, free carboxylic acid is 48 mol / mol
%Met.

Example 2 (Product Containing 1% Polyethylene Glycol) Neutralization Step By treating in the same manner as in Example 1, a 29% aqueous solution of sodium acrylate was obtained. Preparation step of polymerization stock solution (monomer aqueous solution of partially neutralized acrylic acid) 29% aqueous solution of sodium acrylate (3282 g / 1
0.126 mol) and 60% acrylic acid (1180 g /
9.835 mol) of a partially neutralized aqueous solution of acrylic acid (44
Polyethylene glycol (equivalent to 16.6 g / 1%, molecular weight: 20,000) was added to 91 g / 19.961 mol) and dissolved to obtain an about 35% polymerization stock solution (polymer conversion value: 1677 g). Polymerization Step The polymerization stock solution (dissolved oxygen 1 ppm or less / 300 g / 1.337 mol) degassed using nitrogen was added as a catalyst to 22.
5% sodium hypophosphite monohydrate aqueous solution (80 mg /
0.17 mM), a 7.5% aqueous ammonium persulfate solution (120 mg / 0.039 mM) and a 0.75% L-ascorbic acid aqueous solution (80 mg / 0.0034 mM) at an internal temperature of about 20 ° C. (20 ° C.) for about 4 hours and further at an external temperature of about 80 ° C. for about 6 hours. Drying / Pulverization Step The obtained water-containing polymer is granulated, and after about 1 hour at about 140 ° C., further pulverized and dried at about 140 ° C. for 1 to 3 hours, thereby containing 1% of the target polyethylene glycol. Was obtained quantitatively. The pH of the resulting partially neutralized polyacrylic acid containing 1% of polyethylene glycol was 6.
4. The monomer content in the partially neutralized polyacrylic acid is 0.3
%, The rotational viscosity of the partially neutralized polyacrylic acid is 0.1%.
A 2% concentration aqueous solution was mixed with a B-type viscometer (rotor No. 2, 2
0 ° C., 30 rpm), 525 mPa · s,
The free carboxylic acid was 48 mol / mol%.

Example 3 First, tartaric acid (1 g), indomethacin (0.5 g),
Kaolin (3 g), 70% D-sorbitol solution (18
g) and water (50 g). On the other hand, separately from this, the partially neutralized polyacrylic acid obtained in Example 1 (7
g), dihydroxyaluminum aminoacetate (0.1 g) and glycerin (20 g) are mixed. The two mixtures are mixed and uniformly kneaded to obtain a paste-like gel plaster for a patch. This was applied and spread on a nonwoven fabric and protected with a polyethylene film to obtain a patch.

Comparative Example 1 (Product without polyethylene glycol) Example 2 except that polyethylene glycol was not added.
By the same treatment as described above, a partially neutralized polyacrylic acid having the following quality was quantitatively obtained. The pH of the partially neutralized polyacrylic acid without addition of polyethylene glycol was 6.4 in a 0.2% concentration aqueous solution, the monomer content in the partially neutralized polyacrylic acid was 0.3%, The rotational viscosity (30 rpm) of the partially neutralized acrylic acid is 0.2%
The aqueous solution having a concentration of B-type viscometer (rotor No. 2, 20)
C., 30 rpm), 566 mPa · s, and the free carboxylic acid was 48 mol / mol%.

[0046]

According to the present invention, 0.01 to 4% by weight of a polyethylene glycol having an average molecular weight of 3,000 to 50,000 is added to a monomer and polymerized to obtain a gel-like partially neutralized water-containing polyacrylic acid container. The releasability from the manufacturing equipment such as was improved. Thereby, a partially neutralized polyacrylic acid can be efficiently produced. In addition, by using a partially neutralized polyacrylic acid containing polyethylene glycol obtained in the present invention as a thickener such as a poultice, kneading with water or a solvent, etc., with respect to uniformity and solubility. It can be implemented efficiently.

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 4C081 AA03 AA12 BB01 BB04 CA021 CA022 CA052 CA081 CA082 CA182 CB042 CC05 CD032 CD042 CE02 CE11 CF112 DA02 DA05 DA12 DC02 DC03 DC12 DC13 EA02 EA05 4J011 AA01 BA04 PA90 DB02 4J011 GA02 GA06 GA08 4J040 EE022 FA091 HA096 HA156 HA256 HA286 LA01 MA09 MA10 MA15 MB03 NA02 QA01

Claims (8)

[Claims] 1. An aqueous monomer solution containing acrylic acid and an alkali metal salt of acrylic acid as a monomer has an average molecular weight of 30.
A method for producing a gel-like partially neutralized polyacrylic acid, comprising adding 0.01 to 4% by weight of polyethylene glycol of 00 to 50,000 with respect to the total weight of the monomer and polymerizing the same. 2. An aqueous monomer solution containing acrylic acid and an alkali metal salt of acrylic acid as a monomer has an average molecular weight of 30.
A polyacrylic acid moiety comprising adding 0.01 to 4% by weight of polyethylene glycol of 00 to 50,000 with respect to the total weight of the monomer, polymerizing to obtain a gel polymer, and then drying. Method for producing neutralized products. 3. The method according to claim 1, wherein the alkali metal salt of acrylic acid is sodium acrylate. 4. The process according to claim 1, wherein the polymerization is static polymerization. 5. The method according to claim 1, wherein 40 to 60% of the carboxyl groups present in the partially neutralized polyacrylic acid are alkali metal salts. 6. The method according to claim 2, wherein the drying temperature is 110 to 150 ° C. 7. The method according to claim 1, wherein the partially neutralized polyacrylic acid is not substantially crosslinked. 8. A patch using the partially neutralized polyacrylic acid obtained by the production method according to any one of claims 1 to 7.